1. Field of the Invention
The following invention relates to a new and efficient nanoparticles synthesis apparatus and process production. More particularly, the present invention is applied to the synthesis of nanostructured tin dioxide. The benefits provided by the invention are revealed in various gaseous reactions where occurs the formation of solid and gaseous products.
2. Related Art
The nanostructured tin dioxide has properties such as high electrical conductivity, high transparency in the UV-visible region, high thermal resistance, mechanical and chemical resistance and has many applications through microelectronics, manufacturing of opto-electronic devices, solar cells, catalysts, gas sensors, among others. Its major application is in gas sensors production.
Various methods and reactors for the synthesis of tin dioxide are described in the literature, such as the sol-gel method, hydrothermal synthesis, etc. But these methods have limitations that prevent them from being implemented on an industrial scale, such as difficulties in control parameters, high energy cost, complexity, process cost, and generate dangerous co-products, which usually means difficult maintenance and disposal.
The scientific literature and patent research points out some prior art documents related to the present invention. The following paper, Maciel et al., “Nanostructured Tin Dioxide Synthesis and Growth of Nanocrystals and Nanobelts” (New Quim (26) 6, 855-862 (2003)) describes the synthesis of nanostructures of tin dioxide through a solution of supersaturated solid in a process of growth of SnO2 nanoribbons through carbothermal reduction at temperatures ranging from 1100° C. to 1200° C. Another scientific article, Maciel et al., “Nanostructured Tin Dioxide as a NOx Gas Sensor” (Ceramics 49, 163-167 (2003)) describes a process for obtaining nanoparticles of tin dioxide from the dissolved tin citrate, and subsequently particularization of the material obtained. The present invention differs from these documents, for it does not consist of a supersaturated solid solution reaction at high temperatures. The present invention is based on a single process through a gas reaction, using such apparatus at low temperatures (around 200° C.).
The US2010/0294728 document describes a production method of zinc oxide and/or tin dioxide nanoparticles using NaOH. The method comprises the steps of a) selecting a compound from a group of oxides (ZnO, or SnO2); b) making a solution with the base material of these oxides (ZnSO4 or SnCl4); c) dissolving this solution with distilled water; d) mixing the solution obtained; e) adding the NaOH solution until there is formation of a white precipitate; f) pH control and stirring the solution; g) filtering the solution to obtain a precipitate separately; h) drying the sediment; and i) calcifying the precipitate. The present invention differs from this document, for it comprises an apparatus for the production of tin dioxide in the form of nanoparticles and a process for the production of tin dioxide in the form of nanoparticles using such apparatus, which was not described nor suggested in that document.
What is evident from the literature mentioned herein is that no documents were found suggesting or anticipating the teachings of the present invention, so that the solution proposed here possesses novelty and inventive activity against the prior art.